Testing device



Nov. 17, 1925. 1,561,951

L. J. sTAcY TESTING DEVICE Filed Sept..l l'f,Y 1924 Patented Nov. 17,1925.

UNITE-D TES P TiE NT fO'F'Fil-CE LELAND J. STACY, OF CALDWELL, NEW"JERSEY, ASSIGNORKTO 4VVESLERN ELECTRIC i COMPANY, INCORPORATED7 OF'NEWYORK, N. Y., A CORPORATION 10F NEW YORK.

TESTING DEVICE.

yApplication filed September 17,` 1924. Serial No.` 738,204.

.To (1U vta/ioni t may Concern.'

Be it known that l. Lamm) J. citizen of `the United States of America,residing at Caldwell, in the county of Essex, State of Newilersey, haveinvented certain new and useful improvements in Testing" It is wellknown in the art that the ringing trip relays in ordinary telephonesystems must function under rather severe conditions. Such relays mustnot operate when ringing current is applied to the line to ring asubscribers bell but must operateas soon as the called subscriberremoves his receiver 'from the switchhook, at which time Ithe bell andcondenser are shunted by the transmitter and induction coil. As theelectrical characteristics of the lines leading to subscribers` stationsvary to a large degree, due principally to the varying lengths thereof,and the electrical characteristics of the apparatus at the substationsdo not always remain constant due to the different type of apparatusemployed, it is readily seen that the ringing trip relays must functionwithin very narrow limits. The operating characteristics of a ringingtrip relay depend, also, to a considerable extent on the point of thewave of the ringing current at which the circuit for thc relay isclosed. In practice. it has been found that these relaysmay, in someinstances, operate through as high as a 50% higher resistance when thecircuit is closed at the zero point than when it is closed at the peakof a wave, and, as the ringing key may be closed at any point of thewave. it is apparent that the operating limits are, thereby, furtherreduced.

It is an object of the invention to lprovide an arrangement whereby theoperating characteristics of such ringing trip relays may readily betesteil under conditions simulating the most severe conditions`encountered thereby in service.

ginothcr object is the provision of means 'in a testing arrangement ofthis sort for in.- ;'Jjcating the operating characteristics `of aS'raor, a

relay under test in a convenient and accurate manner vvwithout the useof elaborate and costly precision.instruments.

Another object of the invention is `the provision of a Atestingequipment of this type `in a convenient unit, so that tests maybeperformed on the ringing trip relays as actually installed andfunctioning in telephone exchanges and without disturbance to thetelephone system as a whole.

Another object of this invention is the provision of a testing equipmentfor telephone circuit in which any of the standard type of varyingcurrent sources are ernployed.

To attain these objects, in accordance iWith one feature of theinvention, a circuit arrangement has been provided,whereby the terminalsot' a ringing trip relay to be tested may be connected to the testingunit and whereby upon the manipulation ofkeys in this lunit the relay4is subjected to thefull potential from the ringing source when thecurrent therefrom has reached the peak of a` wave.

Another feature of the invention is the provision of means whereby theoperating and non-operating limits for the ringing trip relay aresimulated in the testing' unit by means of non-inductive resistances,and applicable through the operation `of keys.

Another feature resides in Athe provision of a signal inthe testing unitfor indicating the characteristics of a relay under test.

Another feature is the provision in this testing unit of certainstandardtesting conditions to which relays under test may be adjusted torespond.

The invention has been illustratedin the `accoinpanylng drawings, inwhich Fig. 1

ending portion of `an automatic. to, manual machine switching lsystemincluding a ringing .relay `that may .be subject to test byL anarrangement of the Vinvention,as shownjvin '.Flg-

511i `order to more clearly show actual conditions under Which theringing relay will function, the operation of the relay in the inanualtelephone system shown in Fie. l may be briefly outlined as follows:

Then the operator in calling the subscriber at a substation as G insertsher plug 7 in jack 8, a circuit is established as follows: batteryWinding of relay 9, armature and back contact of relay l0, armature andback contact of ringing trip relay 5, sleeve contacts of plug 7 and jack8 to ground.. Relay 9 in operating' now applies ringing current to thesubscribers bell over circuit as follows: alternating` current ringingsource 1l, Winding of relay 5, lower armature and front contact of relay9, ring,l contacts of plug `7 and j ack 8 to the subscriber-s hell atvthe telephone set G, tip contacts of jack 8 and plug 7, upper armatureand front Contact of relay 9 to ground. Under these conditions theringing` trip relay 5 `will not operate due principally to the hit-ghiinpedance of the bell and condenser when the subscriber, in respondingto the call by removing the receiver froin the switchhook, shunts thebell this ringing trip relay 5 is operated. In operating', relay 5 opensthe shunt circuit for relay l0 at its armature and back contact. Relayl0 is, therefore, operated in vseries with relay 9 and in operatingshunts the Winding of relay 9 to battery 1G, causing relay 9 to releaseand thus relnoVe the ringing current frein the line whereupon relay 5releases.

It is readily seen, therefore, that relay 5 must not operate in acircuit containing` the bell and condenser, but operate when these areshunted and therefore function Within very close limits. These liinitsare further restricted as the electrical conditions of this circuit varyto an appreciable extent due principally to the varying resistance ofthe subscribers lines the lengths of which cannot beuniforin as Well asto the varying elecn trical conditions of the substation apparatus. Ithas also been found that the point of a. Wave at which the circuitthrough relay 5 is closed greatly affects the operating characteristicsof this relay, i. e., if foifexainple, the circuit is closed at the Zeropoint of the Wave, the relay will operate at` a inuch higher .resistancein this circuit than .if it is closed at the peak of a Wave. Ittherefore follows that should the ringing relay not be accuratelyadjusted, it might not operate if the circuit through its winding1 wasclosed at the peak of a Wave but function properly if the circuit wasclosed at any other point of the Wave. As an illustration of the closeliniits ordinarily required in telephone systems of this type it mightbe mentioned that the ringing; relay may be required to operate with aresistance of l5() ohrns and not operate with a resistance of 850 ohinsin the circuit.. Considering therefore that the meneer Worst operating;Yconditions are encountered at the peak of a Wave, the test circuitarranged in accordance With this invention has been designed so thatwhen a relay is under test, it is not subjected to the testI until thecurrent from the ringing; source has reached the peak of a Wave and adetailed description of an arrangement on this basis will. nou7 bedescribed.

rllhe test circuit is preferably arranged so that the apparatus, exceptthe battery supply, is contained in a test boze: the outline of which isindicated by a dotted line Q0. This box may include keys 2l, 22, 23 andQ4, rclays 95, 2.5, 27 and 28, signal larnp 2S) and ""3 jacks 30 and 31.In performing' a test a special cord 39. is used, the coinluctors ofwhich are provided with cont-act points or clips 33, 3st and which inaybe connected to the conductors leading to the Winding, and armature andback Contact of relay While plug 36 of this cord is inserted in jack 30and battery and ground are supplied to the 'testing' circuit from plug'38 Which is inserted in jack 3l.

lf relay is to be tested for operation at the peak of a wave underconditions sinnlich ing` the actual. line conditions when the rcceiveris removed front the hook. keys Qt.. 23 are operated and the followinglfunctions take place. Line circuit closed from battery, tip contacts ofplug llt-3 and jack 3l.. one branch extending` through resistance et-O,right hand Winding` of relay inner ric hand armature and back contact ofreta' 1irake-before-ln'ealc contacts of .relay :21, upn per closedcontacts of he); i121 to 'ground at the sleeve contacts of iacl 'Il and.pine While a second branch crt at plc-.g` S8 and `jacl" 4l, lainp Q9,inake-berorclrelay Qi' to ground at plug' it... cuit causes theoperation ot relay io'. where as the second circuit causes l 5125? to bednnly lighted duc to resistance 'llbc or ll" eration. of relay 25 chosesa circuit 'trom bal'-A tery at plug' 38 through resistance hand Windingot relay ture and front contact or rela; i to ,Y

at plug 3S. This causes the operation o lay Q6 which in turn clos acircuit. for the operation of relay il? as i plug,` 38, sleeve contar. sci jack 15o and j; 36, contact armature and. hack Contact o' relay 5,contact 3ft, ring contacts of plus' 23 and jack 30, Winding; et rela;vQ7, richt -lia armatures and front contacts opt and 25 and inner righthaul armature and back Contact of relay to ,aground at plug; 88 `aspreviously traced. Relay 37 in oper t ing', closes a circuit for relay:YS a L; follar u )ner closed contact et ke'y 1 at plug Relay @falso 1teelt-9,51

for lamp 29 i through resistance ll at its niake-betorebreak. contactyand provides a lockingl circuittoritselt' `at its righthand armature`and trent4 Contact to ground ,at plugl 3S. The operation ot relay 2Scloses ,a locking circuit torzitseltl through theainner-i left-handarinatureiand trent contact `which is independent ot the `originalenergizing;- circuit through the ,lettfhand `armature zand .trentcontact et relay 27. illelay QS, in operating, also breaks the originalenergizing vcircuit througheitsinner right-hand urina- `ture `and trentcontact- :forrelays 2?, S36 and 27. Relays 25 and 2o, however, are heldup tliroueh the rielitshandiarn'iature and 'trout `Contact ot`relayZT,,whilerelay it is held up, as previously described. As statedrelay 2T by breaking yits `malte-betore-break contacts opens theenergizine'` circnittor lamp 29 :which is thereby extinguished toindicate `that relays 2ti,2`f;and '28 have tnnctioned properly. 1Relay28 ,now closes :a circuit 4through its `outer-.lett hand armature andtact of relavgQS lett `hand armature and 'front contactot relay winding'ot' relay rresistance fiat to `freund at plngil lt, but as thevaluesotthe resistance ot thelelt-hand windingr ot relay 25 and resistance t0are -sueli as to prevent relay o .troni receiving sutiicientcnrrentfliroin alternating current source 11, this relay `will notoperate at this tiine. Current 'from the alternating current source llthrough the lett-hand winding ot relayQ zmay, however, he, otr-suchdirection that itwvill oppose thedirect current through theright-handwinding'ofrelay to cause it to release, i. e., it relay 28operated `when a negative wave is produced 'trom the alternoting'current source 1.1, nothing will happen, but. it' a positive waveisszpaesing.,Y at this time, relay Q `will heireleased. Upon the releaseot relay, on a positive wave, current t'roni source 1l will non` be`connected through the lett-hand armature and haelt contact` ot` relaylelt hand armature and front` contactot a'elay 26, lett-hand winding otrelay Q6, resistance tl to `ground at plug 238, and relay 2G will thenpresently be released, i..e., as soon as the next negative current isproduced and has `its peak, as it is then in proper direction andstrength to oppose the direct current in the right-hand Windingand causethe release o'lE relay Q6. 'therefore as soon as relay is'` released,this negative current wave which is non' at its peak is sn'itchedat thelett-hand arnrature and `back Contact ot relay 2G through the closedcontacts ot key Q53, resistance, lo, niiddle closed contacts o't'flzey2l to `freund at plug Resistance is ot such value that iseiinnflates thelaotual line coinlitions iarinature and front contact oit' relay 2o,

when the receiver is otlV1 the switchhook and Athe current `trom ther`alternating current ture and back Contact thefcircuit :tor relay 27 andthis relay in releasing closes at its malte-beilore-breal; contacts thefollowing circuit: battery at plug -lt, outer right-hand lamp29malte-betore-hreak Contacts ot relay 27, toground at plug 38. Lamp 2S)is non', brightly illuminated as resistance ftl has been removed tromthe energizing circuit therefor-and this illumination ot lamp 2f servesas an indication that relay 5 hasI operated under the Worst conditionsencountered in practice, that is, at theipeal ot a wave trom thevaryingl source lliandvat the proper line conditions. .The test for theoperation ot relay 5 is now eoinpletednand key 2l may be released,causing relays 2S and 5 to return to normal.

lt' relay 5 is to be tested 't'or a non-operate condition, lteys and 23are actuated an'd the functions ot relays 2G, 2T and 28 and lamp 29 arethe saine Ias previously described, up to the point `where relay hasoperated` when acircuit is in this case com pleted tor relay asYfollows: alternatinp,` cui'- rent `source ll. 'winding ol relay 5,contact 33, tip contacts ot plug` 3o and jack 30, outer lett-handarmature and 'lront contact ot' relay le'litdian'd armatures and hackcontacts ot relays :inland t Vin series through the closed contacts olkey 23, resistances t5 and t6 in series, theiiniddle closed contactsolliey 22, resistance-t7, to ground at plutIv 38. This circuitivhichnon' includes resistances -lt and i-T in addition to resietance-losimulates the actual conditionsencountered in practice l'or thenon-inieration el the ringing relay 5. ltshouldibe noted that in thisinstance itVl relay fris properly adjusted. it u'ill not operate andconsequently relay 2T will remain operated thus the circuit l'orlighting' lamp 2S) is not completed. In this ease, theretore. the non-operatini,r condition o'lI relay 5 is indicated by the non-operationot' lampQl. It' relay his not properly adjusted but would operate inthin latter caso, relay 2T uill release and lamp 29 will he brightlyilluminated to indicate this condition.

Now, in order to adjust relay 5 to `tunetion properly under these testconditions, key 2l. is operated in conjunction with either key 2l or key22, thus changing the resistance conditions by including-a r sistancell-S in series with the resistance if 'tor the opera-tii'ig circuit orincluding the `resisttanee t8 and eliminating the resistance t6 for the.non-operating eiaeujit ,tor relay 5 :sa meneer and thel contacts oitrelay niay new be manually adjusted so that relay operates or does notoperate depending upon which one ot thc keys 2l or 22 is actuated. ltrelay 5 new operates or does not operate with these resistance ialues,in the circuit, it is assumed that it will itunction under the Worstconditions encountered in practice, that is, operate with a resistanceoit the value et resistance etc or not operate Awith a` resistance ofthe combined values ot rcsistances elf, and in other Words, theadjustment is such thata slightly incre seyerc condition than isencountered in practice has to be inet by this relay. i

ltis considered that a detailed description of the operation ot theauton'iatic circuit shown in .li 2 is not necessary, as it torins nopart ot this invention, except to A ay that the ringing' trip relay o()tliercot 'any be tested and adjusted in exactly the saine inanner as Wasrelay 5 by connecting; contacts CSi-, 34tand 35 to the Winding',armature and back Contact of relay 5t), lt should be as' uned that thesequence si'citch n'ell i-z ion'n in thc art and shown in this tiefere,should lic '.t'ere with the proper testing ci relay 5l) and iftnecessary these springs inay he blocl-zed by inserting insulating'strips between the contacts and the springs.

lt should be understood that the intention as disclosed and applied tothe systems described above is not contined to these particulararrangements but inay n'ell be applied to systems in which other typesoli ringing ciu'rent sources are employed, 'tor crainpze, a directcurrent source inay he used; that is the relays .may be adjusted tooperate in a circuit supply comprising shunt current on which anattenuatingg' current has been superimposed. Nor should the invention beconsidered as conlined to the particular use shown but may Well includeother uses such as Afor example, the circuits inay he arranged so thatthe circuit through the ringing; relay is closed at any desired pointolf a navc by phase shit't ot the control. circuits or y use ot tin'iecounting' device' as is Well known in the art. rllliese circuits andrelay coinliinations may also readily be employed to count oli.a anumber ol halt cycles oit the supj'ily curi 1nt or in tact any useinvolving the control or test olE relay as nniy be desired .in themodern telephone j'n'actice tast require the application et theprinciples underlying' the invention as herein disclosed That is claimedis:

l A method of testingl relays consisting;` in subjectinga relay totesting;- current 'troni an alternating; current source at the peak oita. Wave and indicating the result ot the test.

2, A method et testing relays consisting;

in subjecting` a rela-y to a testing current ot' a value to cause itsoperation from an alter-- natingr current source at the peak ot a Waveil said relay is properly adjusted, subjecting said relay to testing'current oit a Value that will not cause its operation troni analterating; current source at the peak of a wave iii said relay isproperly adjusted.

3. A method of testing relays consisting in subjectingl a relay to atesting' current of a value to cause its operation troni an alter*naties' current source at the peak ot a wave it a d relay is properlyadjusted, subjecting said relay to testing' current ot a value that willnot cause its operation trein an alter netting current soin-ce at thepeak of a Wave said relay is jn'operly adjusted and indieating?, theresults of said tests.

l. t method of adj ustinp; relays consistnu' in sulnectinn' a relay to acurrent oit a cert-ani value troni an alternating current source at thepeak oli' a Wave, adjusting' the relay to respond thereto, subjectingsaid relay to a current ot a certain other valut` troni thealtin'natinp,l current source at the peak of a ware and adjusting' therelay so as not to respond thereto.

o. fr method et testing); electr responsive characteristics of relalconsisting' in subjecting' a relay to a testing` c'urreiu; oi" a certainValue troni an alternatini,r current source at the pea-k o'tf a Wave tocanse it to respond it' properly adjusted, sub jecting' said relay to atestine; current of a certain other value 'from an alternating' cur-.rent source at the peak oli a Wave to which it will not respond itproperly adjustedr` subferiing said relay to an adjusting` current of acert-ain other Value 'trom an alternating ciu'rent source at the peak eta Ware, adjust ine said relay to respond to said adjusting current,subjecting' said relay to an adjustingr current of a second Value tronian alternatinir current source at the peak oft a Wave and adjusting saidrelay se as not| to respond to said second ineiiitioned adjusting;`current, the lirst mentioned adjusting; currentV being;` ot' a slightlyhigher Value than the first inentioned testine' current and the secondnientioned adjusting' current beine' oli a slightly loner value than thesecond mentioned test# ing; current.

(i. lfn a system for testine' the electro-responsire cliaractcristics otrelays the combination ol. an alternating' current source and ineans'tor applying current troni said source at the peak oit a Ware to arelay.

i. ln a systeni for testine` the electro-ie sponsirc characteristics otrelays the coinbination et an alternating' current source and leans lorapplyingl current 'troni said source at the peak ot a Wave to a relayand a signaling; ineens ttor indicatingthe response ot said relay.

ln a system for testine; the electro-,re

and adjusting` the sponsive characteristics of relays the combination ofmeans for subjecting' a relay to be tested to currents from said sourceat the peak of a ave and means tor regulating?)l the values oit' saidcurrents so that said relay it' properly adjusted will operate or notoperate according' to the limits set by the Values of the currentapplied. s

9. In a system for testine; the electro-responsive characteristics oirelays the combination ot an alternating' current source and means forsubjecting a relay to be tested to currents from said source at the peakot' a Ware, means for adjusting the value ot the testine' current sothat if said relay is prop` erly adjusted this current will cause it torespond and means for adj ustinfz the value of the testing current sothat it the relay is properly adjusted the current will not cause it torespond.

10. In a system for testing the electron-rfsponsiye characteristics olfa relay the combination of an alternatingl current source, means forsubjecting a relay to loe tested to currentfrom said source at the peakot' a wave, means for adjusting,` the value of the testing current sothat if said relay is properly adjusted this current will cause` it torespond, means for adjustingl the Value ot the testing current so thatit' the relay is properly adjusted it will not respond to said currentand signaling means for indicating,I the response or nonresponse of therelay when subjected to tests with the current adjust-ed to either otsaid values.

ll. In a testing system a testing unit comprisingm ans tor testing' theelectro-responsive characteristics of relays and signaling means toindicate testing' conditions, a relay to be tested. ay source otalternating' current associated with said relay and a cord forconnecting said testing' unit with said relay so that the alternatingcurrent source will serre as a source o'l testing' current and so thatthe contacts of said relay may be included in the control ot saidsignaling means.

In a system for testing' the electro-responsive characteristics otrelays the eon1- bination ot an alternating' current source7 means tor'subjecting' a relay to be tested to a current from said source at. thepeak of a wave, means for regulating the Values o't said current so thatsaid relay if properly adjusted will operate or not operate according tothe limits setby the values of the current applied and means forregulating the values ot said current to cert-ain other limits so thatthe relay may be adjusted to operate or not operate in accordance withsaid second setting` ot the values of the currents applied.

In witness whereof, I hereunto subscribe my name this t3 day o't`September A. D.,

LELAND J. STACY.

